The timing and duration of primary moult in the endemic variable oystercatcher (Haematopus unicolor) are described from 204 records obtained during banding operations and from photographs of birds in flight or wing-stretching. All records were from adults and were collected between 36 degrees and 37 degrees S in northern New Zealand. Records were collected throughout the year, and were analysed using the R package 'moult', which implements the Underhill-Zucchini moult model. Primary moult was not synchronised; the average start date was 04 February, but the 95% confidence limits of start date extended from 12 December to 30 March. The average end date was 08 August (95% confidence limits 15 June to 1 October). Primary moult was therefore very protracted, lasting on average 185 days (6.1 months), and with the whole moult period (first birds to start moult through to the last birds to finish) occupying at least 9.6 months. Birds commonly moulted right through the coldest winter months. This extended moult period is consistent with the fact that adults of this species are non-migratory and highly sedentary. Primary moult also regularly overlapped with breeding. Birds in moult had on average 2.4 primaries active at any time (range = 1-5), with a higher number active while the smaller inner primaries were being re-grown. The gap in the wing caused by primary moult averaged 10% of the total primary feather mass, with a maximum of about 20%. Secondary moult typically began when the primary moult score was in the range 22-30.

The wrybill (Anarhynchus frontalis) is an endemic plover that breeds only in braided rivers east of the main divide in the South Island of New Zealand. It is threatened by a range of factors, including loss and degradation of habitat, flooding, and predation. We monitored wrybills in 2 sites in the Tekapo River and 2 in the Tasman River in the Mackenzie Basin, South Canterbury, during 3 breeding seasons (1997/98-1999/2000). We aimed to compare survival and productivity between areas with and without trapping (mammalian predator control) to determine whether predator control was associated with higher survival and/or breeding success of wrybills. In the Tekapo River, results were similar between trapped and un-trapped areas, suggesting that control had little effect. In the Tasman River, there were large differences between the two sites and trapping appeared to be beneficial; in the upper river (un-trapped), productivity and survival were very low and in the lower (trapped) site they were high. Over the whole study, 67.3% of nests hatched, and depredation was the largest cause of nest failure. Fledging success (the proportion of chicks hatched that fledged) averaged 35.4%. Losses at the chick stage were higher than at the egg stage, and there was only a weak correlation between nesting success and overall breeding success; we therefore caution against the use of nesting success as a proxy for overall breeding success. Productivity averaged 0.49 chicks fledged per pair over the whole study; when the very low values from the upper Tasman site were excluded, productivity averaged 0.61. Survival of adult male wrybills was lower than survival of females in all four study sites. Measurement of adult survival is important in determining the full effect of predator control (and in determining population trends) but is often overlooked. At the time of our study, wrybill populations in 3 of our 4 study sites appeared not to be self-sustaining and, in the absence of immigration, were in decline. A number of factors, including depredation by mammals, can affect breeding success. Trapping may be beneficial, but temporal and geographic differences in predator densities, as well as variability in other threats (such as flooding and levels of avian predation) mean that predicting when and where mammalian predator control may benefit wrybills is currently difficult.

This paper presents the results of four censuses of the northern New Zealand dotterel population undertaken between 1989 and 2011. During that period, the population increased by roughly 50%, from about 1,320 to about 2,130 birds. Most birds (85%) were in the northern part of the North Island (Northland, Auckland, and Coromandel Peninsula), but the taxon is expanding its range southwards on both the west and east coasts. On the east coast, a few pairs are now breeding close to Cook Strait. Population trends varied between regions, and almost all of the overall increase was a result of increases on the east coast. The highest rates of increase were on the Auckland east coast and on Coromandel Peninsula, probably because the intensity of management has been highest in those regions. In the Auckland urban area, birds now routinely breed inland, mainly on grass or bare earth; elsewhere, the taxon is almost entirely coastal. The proportion of birds on the west coast has fallen over the past 50 years, and about 85% of the taxon is now found on the east coast. If the overall increase in numbers has continued at the same rate since 2011, there would be about 2,600 birds in 2020. The size of the population and its rate of increase justify the recent down-listing of the subspecies to a threat ranking of At Risk (Recovering), but it remains Conservation Dependent. The recovery programme has been highly successful, and most management of the taxon is now undertaken by community groups, regional councils, and volunteers. Continuing threats include predation, flooding of nests, and disturbance during breeding; in future, continuing coastal development and increased recreational activity will probably degrade habitat further, particularly on the east coast, and climate change will have a range of impacts.

The endemic fauna of New Zealand evolved in the absence of mammalian predators and the introduction of the latter has been devastating. There have been numerous avian extinctions and 80% of the extant native avian taxa are currently threatened or at risk of extinction. Declines continue, and a fundamental change in predator management is required. In 2016 came the announcement of the ambitious Predator Free 2050 (PF 2050) programme, which aims to eradicate rats, mustelids, and Brushtail Possums from New Zealand by 2050. This paper reviews some of the many techniques being discussed or developed to implement the programme. Existing techniques are being refined and new tools are being developed. Research on new toxins, including those with potentially higher species specificity, is under way, and novel baits and toxin-delivery devices are being developed. Existing trap designs are being refined, and new self-resetting traps capable of multiple kills have been developed. Research is also under way on new lures and repellents. Eradications may be achieved in stages, and barriers (both natural and artificial) will be needed to protect areas already cleared. Current techniques will probably be inadequate to effect nationwide eradications, and new tools (possibly based on genetic technologies) will probably be required. Regulatory hurdles will need to be overcome, and community consultation and support (social licence) will be required throughout the programme. The use of some new technologies may be contentious, and not every new idea will necessarily be adopted. Technical, social, and organisational challenges exist, and national and international collaboration will be required for PF 2050 to succeed.

The shore plover (Thinornis novaeseelandiae) is a highly threatened shorebird endemic to New Zealand. It is particularly susceptible to introduced mammalian predators, and has a very small total population and a very limited range. This paper lists the translocations that have formed the core of the shore plover recovery programme over the past 22 years, and summarises the outcomes. In the early 1990s, a captive population was established in mainland New Zealand using birds reared from eggs transferred from the last self-sustaining wild population on the Chatham Islands. Since 1994, captive-bred birds have been released on 5 offshore islands around the New Zealand mainland in attempts to found new populations. There have also been transfers of wild-bred birds from South East I to Mangere I in the Chatham Is. Between 1994 and April 2012, 404 juvenile and 28 adult shore plover have been released at a total of 6 sites. Birds bred at 4 of the 6 sites, and breeding populations established at 3 of them. However, recent mammalian predator incursions at 1 (and probably 2) of those, and habitat limitation at the 3 rd , mean that the translocated populations are all currently small (6 pairs or less), and their long-term future is uncertain. Other challenges faced during the programme include avian predation of released birds, high rates of dispersal, and outbreaks of avian pox. In spite of recent setbacks, the risk of extinction for the species has gradually been reduced. Since 1990, a self-sustaining captive population has been set up, the number of breeding pairs has increased, and the number of breeding populations in the wild has risen from 2 to 4 (although 1 is currently facing extirpation). Features of the shore plover programme that have contributed to these outcomes are outlined. Aspects of shore plover ecology revealed by the translocations are noted. While progress has been made, existing populations will need to grow, and further populations will need to be established before the shore plover's threat ranking improves.

We present the first detailed data on the Great Barrier Island (GBI) subpopulation of the northern New Zealand dotterel (NNZD; Charadrius obscurus aquilonius). The breeding season population has averaged 48 birds (range: 41- 64) since 2000. At Awana on GBI, productivity has averaged >1.0 fledged chick per pair-year. The apparent survivorship of adult birds was less than that in the North Auckland subpopulation. After breeding, most GBI birds congregated at Whangapoua Estuary/Okiwi Spit in the north of the island, making this a site of international importance under the Ramsar Convention (1971). The post-breeding population of c.56 birds (range: 41 - 77) was augmented by local juveniles and input from elsewhere. Banding returns provided evidence of movement between GBI and the adjacent mainland subpopulation on the Coromandel Peninsula. There was no evidence that fewer predatory mammal species on GBI benefits the species at present. Conservation emphasis should focus on controlling mammalian predators and managing human impacts at breeding sites, especially early in the breeding season.

Population size and breeding success of northern New Zealand dotterels (Charadrius obscurus aquilonius) were studied on the recently mammalian predator-eradicated Motuihe Island in the Hauraki Gulf, New Zealand. The island’s entire breeding population was monitored during the austral breeding season from Nov 2007 – Feb 2008. Nine breeding pairs were identified and their breeding success recorded. A total of 41% of nesting attempts produced fledglings and 1.22 chicks fledged per pair for the season; each egg had a 38% chance of survival to fledging. The breeding success of this endemic shorebird was twice as high on Motuihe Island as that at unmanaged mainland sites, and is comparable to levels of breeding success at other managed sites with mammal trapping or predator-proof fencing. The only identified cause of nesting failure over the breeding season was avian predation. Suggestions are made to maintain and enhance breeding success at this locality.

Summary 1. Eradication of a single pest species from a multiply invaded island system may have unpredicted and detrimental impacts. Bergstrom et al. (2009) describe damage to vegetation following an increase in the number of rabbits on Macquarie Island. They propose that the increase in rabbit numbers was caused solely by eradication of cats. 2. However, their modelling is flawed and their conclusion that cats were controlling rabbit numbers is unsupported. We suggest the increase was because of some combination of four factors: reduced releases of Myxoma virus, abundant food after 20 years of vegetation recovery, release from cat predation and climate variability. 3. Recent high numbers of rabbits on Macquarie Island are not unprecedented; vegetation has been damaged in the past but has recovered. Rabbit numbers appear to be in decline again in the absence of both cats and Myxoma releases, suggesting that other factors can contribute to regulation of rabbit numbers in this system. 4. We do not agree with the implication that pest management could have been better integrated. Eradication techniques for rodents and rabbits on an island the size of Macquarie were unavailable when cat eradication was deemed necessary. The benefits to seabirds of cat eradication have been rapid. Our analysis further highlights the complexity of multiply invaded island ecosystems.

Summary 1. Eradication of a single pest species from a multiply invaded island system may have unpredicted and detrimental impacts. Bergstrom et al. (2009) describe damage to vegetation following an increase in the number of rabbits on Macquarie Island. They propose that the increase in rabbit numbers was caused solely by eradication of cats. 2. However, their modelling is flawed and their conclusion that cats were controlling rabbit numbers is unsupported. We suggest the increase was because of some combination of four factors: reduced releases of Myxoma virus, abundant food after 20 years of vegetation recovery, release from cat predation and climate variability. 3. Recent high numbers of rabbits on Macquarie Island are not unprecedented; vegetation has been damaged in the past but has recovered. Rabbit numbers appear to be in decline again in the absence of both cats and Myxoma releases, suggesting that other factors can contribute to regulation of rabbit numbers in this system. 4. We do not agree with the implication that pest management could have been better integrated. Eradication techniques for rodents and rabbits on an island the size of Macquarie were unavailable when cat eradication was deemed necessary. The benefits to seabirds of cat eradication have been rapid. Our analysis further highlights the complexity of multiply invaded island ecosystems.

The anticoagulant brodifacoum is widely used for the control and eradication of vertebrate pests in New Zealand. During poisoning operations with this toxin, some native birds eat baits and die. Because brodifacoum persists in the environment, other birds may suffer secondary poisoning from eating animals that have ingested the poison baits.We describe here high mortality of New Zealand dotterels (Charadrius obscurus) following an aerial brodifacoum operation at Tawharanui Regional Park, North Auckland, in 2004. At least 50% of the dotterels in the area at the time of the operation disappeared or were found dead; one bird found freshly dead had a high liver level of brodifacoum residue. Sandhoppers (Talorchestia spp.) are a common food item of New Zealand dotterels. Sandhoppers at Tawharanui ate baits and accumulated brodifacoum and provided a potential route for transmission of the toxin to dotterels. Three pied stilts (Himantopus himantopus) and one spur-winged plover (Vanellus miles novaehollandiae) were also found dead. These records appear to be the first to document probable secondary poisoning of shorebirds in New Zealand. There was no apparent mortality of variable oystercatchers (Haematopus unicolor). Measures are suggested to reduce shorebird mortality in future operations of this type. Monitoring of New Zealand dotterels and other shorebirds during other types of poisoning operations in coastal areas is also recommended.

Concentrations of mercury, lead and cadmium were determined in whole blood samples from South Island pied oystercatchers Haematopus ostralegus finschi from two over-wintering sites within the Auckland region, New Zealand. The sites chosen reflected divergent pollutant regimes; South Kaipara Harbour was relatively free of urbanisation and associated pollution, whilst Mangere Inlet within Manukau Harbour in central Auckland was considered relatively polluted. Mercury concentrations in bird blood samples were relatively low (maximum concentration=102.4 ng g−1 wet weight in a juvenile from Mangere Inlet), and exhibited no differences between age categories, nor between the two sites. Mercury concentrations measured in oystercatchers were highly unlikely to result in any deleterious toxicological effects. Mean lead concentration was markedly and significantly higher in birds from Mangere Inlet (overall mean=143.1 ng g−1 wet weight) compared to that in birds from South Kaipara (overall mean=58.2 ng g−1 wet weight). Within birds from Mangere Inlet, juveniles exhibited a significantly higher mean lead concentration (184.0 ng g−1 wet weight) compared to that in adults (113.0 ng g−1 wet weight). Some individuals sampled at Mangere Inlet exhibited blood lead concentrations above the 200 ng g−1 wet weight ‘threshold’ generally considered to define the concentration at and above which there is potential for toxicological effects. Cadmium concentrations were uniformly low in birds from both sites, often below detection limits, and pose no toxicological threat. The suitability of analysing heavy metals in blood from South Island pied oystercatchers in order to elucidate patterns of metal contamination over relatively small spatial scales is discussed.

Summary: We studied the ecology of a high-density population of stoats in Fiordland, New Zealand, in the summer and autumn of 1990-91 following a Nothofagus seeding in 1990. Results are compared with findings from the same area in 1991-92, a period of lower stoat density. In the high-density year, minimum home ranges (revealed by radio-tracking) of four females averaged 69 ha and those of three males 93 ha; range lengths averaged 1.3 km and 2.5 km respectively. Neither difference was statistically significant. For combined sexes, average range area in the high-density year was significantly less, and range length was significantly shorter, than in the following year. When we compared stoat diet in the high-density year with that in the following two years, there were no significant differences in the frequencies of occurrence of birds or invertebrates in stoat guts. Overall, bird remains were found in 56% of guts, and invertebrates in 28%. Possum remains occurred in 6% of male stoats but were never found in females. Mice were only detected in stoats in the high-density year, when they occurred in 54% of guts. Lagomorphs occurred significantly more often in the guts of stoats during lowerdensity years (26%) than the high-density year (7%). Seedfall in Nothofagus forest is synchronous and periodic. Following seedfall, mouse density rises dramatically, followed by a sharp rise in stoat numbers. It has been suggested that mice feed on the abundant seed and that stoats in turn increase because of the large numbers of mice available to them. We suggest that the situation is more complex and that increases in not only mouse, but also bird (and possibly invertebrate), densities may contribute to the high productivity of stoats in the year following a Nothofagus seedfall.

Publisher Summary This chapter describes the isolation and assay procedures currently used in the study of the nine aminoglycoside-modifying enzymes. The enzymes—that modify the aminoglycoside or aminocyclitol antibiotics—have been detected in a wide variety of resistant bacteria. In many clinical isolates, they are known to be plasmid-coded. In certain strains, the enzymes appear to be located near the cell surface. The study of these enzymes is particularly valuable for two reasons. First, determination of the type and site of modification have allowed the design and synthesis of semisynthetic antibiotics not modified by the enzyme and therefore active against many resistant isolates. Second, the enzymes provide a very sensitive, rapid, and often specific assay for the aminoglycoside antibiotics. Enzyme activities are assayed by means of the phosphocellulose paper-binding assay, which measures transfer of radiolabel from a suitable cofactor to the antibiotic.